Sacroiliac Joint Stabilization Prostheses

ABSTRACT

Prostheses are described for stabilizing dysfunctional sacroiliac (SI) joints. The prostheses are sized and configured to be press-fit into surgically created pilot SI joint openings in dysfunctional SI joint structures. The prostheses have a pontoon shape with opposed elongated partially cylindrical sections connected by a bridge section. The partially cylindrical sections and, in some instances, the bridge section have a porous structure.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/463,831, filed Sep. 1, 2021, which is a continuation-in-partapplication of U.S. patent application Ser. No. 13/857,977, filed Apr.5, 2013, now U.S. Pat. No. 11,273,042, which is a continuationapplication of U.S. patent application Ser. No. 13/192,289, filed Jul.27, 2011, now abandoned, which claims the benefit of U.S. provisionalpatent application Ser. No. 61/368,233, filed Jul. 27, 2010.

FIELD OF THE INVENTION

The present invention relates to methods, systems and apparatus forstabilizing junctions between bone structures. More particularly, thepresent invention relates to methods, systems and apparatus forstabilizing dysfunctional sacroiliac (SI) joints.

BACKGROUND OF THE INVENTION

As is well known in the art, the sacroiliac (SI) joint 6 comprises adiarthrodial synovial joint, which, as illustrated in FIG. 1A, isdefined by the interface between the articular surfaces of the sacrum 2and the ilium 4. Thus, the SI joint 6 is defined by (and, hence,comprises) portions of the sacrum 2 and ilium 4.

As is also well known in the art, the SI joint further comprisesarticular cartilage, i.e., hyaline and fibrocartilage, and a strong,extensive ligamentous architecture, which stabilizes the SI joint.

Generally, the articular surfaces of the sacrum 2 and the ilium 4 thatdefine the SI joint 6 comprise cortical bone 8, which is more compact,dense and hard relative to softer trabecular bone 10, which, as furtherillustrated in FIG. 1A, is disposed in the interior regions of thesacrum and ilium 2, 4.

The SI Joint is distinguished from other synovial joints by the atypicalarticulation of the different articular surfaces of the sacrum andilium; the articular surface of the sacrum comprising hyaline cartilageand the articular surface of the ilium comprising substantially strongerfibrocartilage.

As is further well known in the art, the primary plane of motion of theSI joint is anterior-posterior along a transverse axis. The terms oftenemployed to describe the relative motion of the sacrum and ilium arenutation, which refers to anterior-inferior movement of the sacrum whilethe coccyx (denoted “3” in FIG. 1A) moves posteriorly relative to theilium, and counternutation, which refers to posterior-superior movementof the sacrum while the coccyx moves anteriorly relative to the ilium.

In most healthy individuals, the SI joint range of motion inflexion-extension is approximately 3°, approximately 1.5° in axialrotation and approximately 0.8° in lateral bending.

As is well established, the SI joint performs several seminalbiomechanical functions. The primary functions of the SI joint are toattenuate loads exerted on the upper body and to distribute the loads tothe lower extremities. The SI joint also functions as a shock absorberfor loads exerted on spine.

As is also well established, the noted loads and, hence, forces exertedon the SI joint can adversely affect the biomechanical functions of theSI joint, which can, and often will, result in SI joint dysfunction—anoften-overlooked musculoskeletal pathology associated with lower backpain.

Indeed, SI joint dysfunction is estimated to be the primary cause oflower back pain in 15-30% of subjects afflicted with such pain. However,lower back pain associated with SI joint dysfunction is suspected to befar more common than most healthcare providers realize, since such painis often associated with other skeletal and musculoskeletaldysfunctions.

SI joint dysfunction, and pain associated therewith, can be caused byvarious SI joint abnormalities and/or disorders, including traumaticfracture dislocation of the pelvis, degenerative arthritis,sacroiliitis, i.e., an inflammation or degenerative condition of thesacroiliac joint; osteitis condensans ilii, and other degenerativeconditions of the SI joint structures.

Various non-surgical methods, such as administration of pharmacologicalagents, e.g., the corticosteroid prednisone, and surgical methods anddevices, i.e., prostheses, have been developed and employed to treat SIjoint dysfunction.

The most common approach employed to treat SI joint dysfunctions (whennon-surgical treatments fail to ameliorate pain associated therewith),at present, is SI joint stabilization, i.e., reinforcing or modulatingarticulation by and between the sacrum and ilium, via surgicalintervention.

SI joint stabilization typically comprises surgical placement of aprosthesis proximate to or in a dysfunctional SI joint and is generallycharacterized by the direction of access to the dysfunctional SI joint,i.e., anterior, posterior or lateral.

Although several conventional SI joint stabilization surgical methodsand associated bone prostheses have effectively ameliorated painassociated with SI joint dysfunction, there remains many disadvantagesassociated with the conventional methods and associated prostheses.

A major disadvantage associated with many conventional SI jointstabilization surgical methods is that the surgeon is required to make asubstantial incision in and through the skin and tissues of a subject toaccess the dysfunctional SI joint. Often referred to as “open surgery”methods, these surgical methods have the attendant disadvantages ofrequiring general anesthesia and often involve increased operative time,pain, hospitalization, and recovery time due to the extensive softtissue damage. There is also an increased probability of post-surgicalcomplication associated with open surgery methods, such as nosocomialinfection.

Minimally-invasive methods for SI joint stabilization have thus beendeveloped to address the noted disadvantages associated with opensurgery methods. Although conventional minimally-invasive SI jointstabilization methods, such as the methods disclosed in U.S. Pub. No.2009/0076551 to Petersen, have garnered some success in relieving painassociated with SI joint dysfunction and have effectively addressed manyof the disadvantages associated with open surgery methods, theresimilarly remains many disadvantages associated with conventionalminimally-invasive SI joint stabilization methods.

A major disadvantage associated with many conventionalminimally-invasive SI joint stabilization methods is that such methodsare difficult to perform and, hence, often require extensive,system-specific surgical training and experience. Despite the level ofsurgical training and experience that surgeons possess, when suchconventional minimally-invasive SI joint stabilization methods areemployed, there is still a substantial incidence of damage to thelumbosacral neurovascular structures proximate to the SI joint.

A further disadvantage associated with many conventionalminimally-invasive SI joint stabilization methods and associatedapparatus, i.e., prostheses, such as the methods and prosthesesdisclosed in U.S. Pub. No. 2009/0076551 to Petersen, is thatpre-existing sacral abnormalities can lead to displacement of theimplanted prostheses, which can, and often will result in damage tosurrounding bone and soft tissue structures.

An additional disadvantage associated with many conventional minimallyinvasive SI joint stabilization methods is that they comprise anterioror lateral approaches to the dysfunctional SI joint and, hence, muscles,e.g., gluteal aponeurotic fascia and gluteus medius, and ligaments aretypically disrupted, and nerves and blood vessels are susceptible todamage during placement of a prosthesis in a dysfunctional SI joint.

Further, some conventional minimally-invasive SI joint stabilizationmethods are particularly prone to failure due to displacement of theprostheses in the dysfunctional SI joint and/or failure of theprostheses to effectively engage the SI joint structures, e.g.,articular surfaces of the sacrum and/or ilium.

Various “improved” prostheses have thus been developed for use inminimally-invasive SI joint stabilization methods or procedures toeffectively engage SI joint structures and maintain engagement theretoduring SI joint function.

Although many of the “improved” prostheses, when deployed properly in adysfunctional SI joint, can, and often will, effectively engage SI jointstructures, there remains several disadvantages associated with theprostheses. Illustrative are the prostheses disclosed in U.S. Pat. No.8,951,254 to Mayer, et al.

The prostheses disclosed in U.S. Pat. No. 8,951,254 comprise or arecoated with a liquefiable synthetic polymer that is adapted to liquifyupon administration of mechanical energy, e.g., high frequencyvibration, when implanted and re-solidify thereafter to securely engagethe SI joint structures, i.e., sacrum and ilium.

A major disadvantage associated with the prostheses disclosed in U.S.Pat. No. 8,951,254 is that the liquefiable synthetic polymers, whenre-solidified in situ, are structurally inferior to the osseous or bonetissue of the sacrum and ilium. The fusion sites between the articularsurfaces of the sacrum and ilium that define the SI joint are, thus,highly susceptible to structural fatigue and failure, which can, andoften will, result in misalignment of the SI joint and ultimatelyincreased pain for the subject.

A further disadvantage associated with the prostheses disclosed in U.S.Pat. No. 8,951,254 is that the synthetic liquefiable synthetic polymersare also substantially immunogenic and will induce an adverse immuneresponse when the prostheses are implanted in a dysfunctional SI joint.As is well established, the adverse immune response can, and often will,prevent healing and osteogenic processes, e.g., remodeling of damagedosseous tissue and regeneration of new osseous tissue.

Additional disadvantages associated with the prostheses disclosed inU.S. Pat. No. 8,951,254 and many other prostheses designed forminimally-invasive SI joint stabilization are that the noted prosthesesare difficult to accurately place in optimum positions in adysfunctional SI joint and, in many instances, lack sufficientstructural properties, such as rigidity and/or fatigue resistance, toeffectively stabilize the dysfunctional SI joint.

It would thus be desirable to provide SI joint stabilization systems andapparatus, which substantially reduce or eliminate the disadvantagesassociated with conventional SI joint stabilization systems andapparatus.

It is therefore an object of the invention to provide improved SI jointstabilization systems and apparatus, which substantially reduce oreliminate the disadvantages associated with conventional SI jointstabilization systems and apparatus.

It is another object of the invention to provide improvedminimally-invasive SI joint stabilization systems and apparatus, whichcan be readily employed to place prostheses in and, thereby, stabilizedysfunctional SI joints via a posterior approach.

It is another object of the invention to provide improvedminimally-invasive SI joint stabilization systems and apparatus, whichcan be readily employed to stabilize dysfunctional SI joints.

It is another object of the invention to provide improvedminimally-invasive SI joint stabilization systems and apparatus, which,when implanted in a dysfunctional SI joint, effectively ameliorate painassociated with the SI joint dysfunction.

It is another object of the invention to provide improved SI jointprostheses that can readily be employed in minimally-invasive SI jointstabilization methods and provide secure engagement to SI jointstructures.

It is another object of the invention to provide improved SI jointprostheses that can readily be employed in minimally-invasive SI jointstabilization methods and possess optimal structural properties toeffectively stabilize dysfunctional SI joints.

It is yet another object of the invention to provide improved SI jointprostheses that can readily be employed in minimally-invasive SI jointstabilization methods and facilitate remodeling of damaged osseoustissue and regeneration of new osseous tissue and osseous tissuestructures.

SUMMARY OF THE INVENTION

The present invention is directed to minimally-invasive methods, systemsand apparatus for stabilizing dysfunctional SI joints.

In some embodiments of the invention, there are thus providedminimally-invasive apparatus for stabilizing dysfunctional SI joints. Inone embodiment, the minimally-invasive apparatus comprises a SI JointStabilization Prosthesis comprising:

an elongated prosthesis structure adapted to be implanted in adysfunctional SI joint via a posterior approach, the dysfunctional SIjoint being disposed between and defined by a sacrum bone structure andan ilium bone structure,

the elongated prosthesis structure comprising first and second elongatedpartially cylindrical sections connected to a bridge section,

the first elongated partially cylindrical section and the secondelongated partially cylindrical section comprising a porous structure,

the elongated prosthesis structure comprising a prosthesis proximal endand a prosthesis distal end disposed opposite the first proximal end,

the bridge section comprising a bridge section proximal end and a bridgesection distal end disposed opposite the bridge section proximal end andproximate the elongated prosthesis distal end,

the bridge section distal end comprising a first tapered regionconfigured and adapted to disrupt at least articular cartilage andcortical bone,

the first elongated partially cylindrical section comprising a firstinternal lumen,

the second elongated partially cylindrical section comprising a secondinternal lumen,

In some embodiments, the bridge section also comprises a porousstructure.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages will become apparent from the followingand more particular description of the preferred embodiments of theinvention, as illustrated in the accompanying drawings, and in whichlike referenced characters generally refer to the same parts or elementsthroughout the views, and in which:

FIG. 1A is a schematic illustration of a human pelvic region from ananteroposterior (AP) perspective showing the SI joints thereof;

FIG. 1B is another schematic illustration of a human pelvic region froma posterior perspective showing the adjoining sacrum and ilium bonestructures, and ligamentous structures thereof;

FIG. 1C is a schematic illustration of the sacrum and coccyx from alateral perspective showing the sacral promontory and the articularsurface of sacrum;

FIG. 2A is an illustration of a SI joint from a superior perspectiveshowing the adjoining sacrum and ilium articular surfaces;

FIG. 2B is another illustration of a SI joint from a posteriorperspective showing the adjoining sacrum and ilium articular surfaces;

FIG. 2C is a further illustration of the SI joint shown in FIG. 2Ashowing lateral and posterior approaches to the SI joint, in accordancewith the invention;

FIG. 3A is a further illustration of the SI joint shown in FIG. 2Ashowing an elongated guide probe of the invention positioned in the SIjoint, in accordance with the invention;

FIG. 3B is a further illustration of the SI joint shown in FIG. 3Ashowing one embodiment of a defect creation assembly disposed proximatethe SI joint, in accordance with the invention;

FIG. 3C is a perspective view of the defect creation assembly shown inFIG. 3B, in accordance with the invention;

FIG. 4A is a further illustration of the SI joint shown in FIG. 2Bshowing one embodiment of a pilot SI joint opening, in accordance withthe invention;

FIGS. 4B and 4C are illustrations of further embodiments of SI jointopenings, in accordance with the invention;

FIG. 5A is a perspective view of one embodiment of a prosthesisdeployment assembly, in accordance with the invention;

FIG. 5B is a front plan view of the prosthesis deployment assembly shownin FIG. 5A, in accordance with the invention;

FIG. 5C is a left side plan view of the prosthesis deployment assemblyshown in FIG. 5A, in accordance with the invention;

FIG. 5D is a top plan view of the prosthesis deployment assembly shownin FIG. 5A, in accordance with the invention;

FIG. 5E is a bottom plan view of the prosthesis deployment assemblyshown in FIG. 5A, in accordance with the invention;

FIG. 5F is a front plan view of a prosthesis engagement rod of theprosthesis deployment assembly shown in FIG. 5A, in accordance with theinvention;

FIG. 5G is a perspective view of the prosthesis deployment assemblyshown in FIG. 5A engaged to a prosthesis of the invention, in accordancewith the invention;

FIG. 6A is a perspective view of one embodiment of a prosthesis, inaccordance with the invention;

FIG. 6B is a top plan view of the prosthesis shown in FIG. 6A, inaccordance with the invention;

FIG. 6C is a rear plan view of the prosthesis shown in FIG. 6A, inaccordance with the invention;

FIG. 6D is a front plan view of the prosthesis shown in FIG. 6A, inaccordance with the invention;

FIG. 6E is a rear perspective view of the prosthesis shown in FIG. 6A,in accordance with the invention;

FIG. 6F is a front perspective view of the prosthesis shown in FIG. 6A,in accordance with the invention;

FIG. 6G is a right-side plan view of the prosthesis shown in FIG. 6A, inaccordance with the invention;

FIG. 6H is a right-side sectional plan view of the prosthesis shown inFIG. 6A, in accordance with the invention;

FIG. 6I is another rear plan view of the prosthesis shown in FIG. 6Ashowing the cross-sectional shape defined by the outer surface of theprosthesis, in accordance with the invention;

FIG. 7A is an illustration of the prosthesis shown in FIG. 6A insertedinto the pilot SI joint opening shown in FIG. 4A and the resulting orinduced post-prosthesis insertion SI joint opening, in accordance withthe invention;

FIG. 7B is an illustration of the prosthesis shown in FIG. 6A insertedin the pilot SI joint opening shown in FIG. 4B and the resulting orinduced post-prosthesis insertion SI joint opening, in accordance withthe invention;

FIG. 8A is an illustration of the post-prosthesis insertion SI jointopening generated or induced when the prosthesis shown in FIG. 6A isinserted in the pilot SI joint opening shown in FIG. 4A, in accordancewith the invention;

FIG. 8B is an illustration of the post-prosthesis insertion SI jointopening generated or induced when the prosthesis shown in FIG. 6A isinserted in the pilot SI joint opening shown in FIG. 4B and/or 4C, inaccordance with the invention;

FIG. 9A is a perspective view of one embodiment of drill guide assembly,in accordance with the invention;

FIG. 9B is a perspective view the access sleeve of the drill guideassembly shown in FIG. 9A, in accordance with the invention;

FIG. 9C is a front plan view of the access sleeve shown in FIG. 9B, inaccordance with the invention;

FIG. 9D is a right-side plan view of the access sleeve shown in FIG. 9B,in accordance with the invention;

FIG. 9E is a perspective view of one embodiment of an access sleevehandle that is configured to engage the access sleeve shown in FIG. 9B,in accordance with the invention;

FIG. 9F is an end plan view of the access sleeve handle shown in FIG.9E, in accordance with the invention;

FIG. 9G is a perspective view of the drill guide of the drill guideassembly shown in FIG. 9A, in accordance with the invention;

FIG. 9H is a front plan view of the drill guide shown in FIG. 9G, inaccordance with the invention;

FIG. 9I is a top plan view of the drill guide shown in FIG. 9G, inaccordance with the invention;

FIG. 9J is a bottom plan view of the drill guide shown in FIG. 9G, inaccordance with the invention;

FIG. 9K is a perspective view of the guide pin of the drill guideassembly shown in FIG. 9A, in accordance with the invention;

FIG. 9L is a perspective view of the bone dislodging apparatus, i.e.,drill bit, shown in FIG. 9A, in accordance with the invention;

FIG. 10A is a perspective view of one embodiment of a prosthesisextraction assembly, in accordance with the invention;

FIG. 10B is a front plan sectional view of the prosthesis extraction rodof the prosthesis extraction assembly shown in FIG. 10A, in accordancewith the invention;

FIG. 10C is a partial section, front sectional plan view of the threadedend of the prosthesis extraction rod shown in FIG. 10B, in accordancewith the invention;

FIG. 10D is a perspective view of the extraction fork of the prosthesisextraction assembly shown in FIG. 10A, in accordance with the invention;

FIG. 10E is a front plan view of the extraction fork shown in FIG. 10D,in accordance with the invention;

FIG. 10F is a top plan view of the extraction fork shown in FIG. 10D, inaccordance with the invention;

FIG. 10G is an exploded view of the slap hammer assembly of theprosthesis extraction assembly shown in FIG. 10A, in accordance with theinvention;

FIGS. 11A and 11B are CT scan images of a patient's SI joint at six (6)months following an SI joint stabilization procedure with the prosthesisshown in FIG. 6A, in accordance with the invention; and

FIG. 12 is a graphical illustration of a patient's visual analog painscore over a six (6) week period of time following an SI jointstabilization procedure with the prosthesis shown in FIG. 6A, inaccordance with the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Before describing the present invention in detail, it is to beunderstood that this invention is not limited to particularlyexemplified apparatus, systems, structures or methods as such may, ofcourse, vary. Thus, although a number of apparatus, systems and methodssimilar or equivalent to those described herein can be used in thepractice of the present invention, the preferred apparatus, systems,structures and methods are described herein.

It is also to be understood that, although the present invention isdescribed and illustrated in connection with sacroiliac (SI) jointstabilization, fixation and fusion procedures, the invention is notlimited to such procedures. According to the invention, the apparatus,systems and methods of the invention can also be employed to stabilizeand/or fuse other articulating bone structures, including, withoutlimitation, spinal vertebrae, tarsal bones and the like.

It is also to be understood that the terminology used herein is for thepurpose of describing particular embodiments of the invention only andis not intended to be limiting.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one having ordinaryskill in the art to which the invention pertains.

Further, all publications, patents and patent applications cited herein,whether supra or infra, are hereby incorporated by reference in theirentirety.

As used in this specification and the appended claims, the singularforms “a, “an” and “the” include plural referents unless the contentclearly dictates otherwise. Thus, for example, reference to “anincision” includes two or more incisions and the like.

Further, ranges can be expressed herein as from “about” or“approximately” one particular value, and/or to “about” or“approximately” another particular value. When such a range isexpressed, another embodiment includes from the one particular valueand/or to the other particular value. Similarly, when values areexpressed as approximations, by use of the antecedent “about” or“approximately”, it will be understood that the particular value formsanother embodiment. It will be further understood that the endpoints ofeach of the ranges are significant both in relation to the otherendpoint, and independently of the other endpoint.

It is also understood that there are a number of values disclosedherein, and that each value is also herein disclosed as “about” or“approximately” that particular value in addition to the value itself.For example, if the value “10” is disclosed, then “approximately 10” isalso disclosed. It is also understood that when a value is disclosedthat “less than or equal to” the value, “greater than or equal to thevalue” and possible ranges between values are also disclosed, asappropriately understood by the skilled artisan. For example, if thevalue “10” is disclosed then “less than or equal to 10” as well as“greater than or equal to 10” is also disclosed.

Definitions

The terms “sacroiliac joint”, “SI joint”, “sacroiliac junction” and “SIjunction” are used interchangeably herein, and mean and include anyregion proximate to articulating regions of the sacrum and ilium bonestructures and, hence, a junction between and defined by sacrum andilium bone structures.

The term “dysfunctional” as used in connection with a SI joint, meansand includes a physiological abnormality, disorder or impairment of anSI joint, including, but limited to, traumatic fracture dislocation ofthe pelvis, degenerative arthritis, sacroiliitis, i.e., an inflammationor degenerative condition of the SI joint; osteitis condensans ilii, andother degenerative conditions of SI joint bone structures.

The terms “articular surface” and “articulating surface” are usedinterchangeably herein in connection with bone structures; particularly,the sacrum and ilium bone structures, and mean and include a surface ofa bone structure that forms an articulating junction (i.e., a synovialjoint) with an adjacent bone structure, e.g., the articular surfaces ofthe sacrum and ilium bone structures.

The terms “fusion” and “arthrodesis” are used interchangeably herein inconnection with bone structures, and mean and include partial orcomplete immobilization of adjacent bone structures; particularly, thesacrum and ilium bone structures.

The term “stabilization”, as used herein, means and includesreinforcing, e.g., supporting, or modulating motion of adjacentarticular bone structures; particularly, the sacrum and ilium bonestructures. The term “stabilization”, thus, in some instances, means andincludes fusion and arthrodesis of adjacent bone structures.

The term “prosthesis”, as used herein in connection with bonestructures, means and includes a system or apparatus configured andadapted to stabilize or modulate motion of articulating bone structures;particularly, the sacrum and ilium bone structures.

The term “biodegradable”, as used herein, means the ability of amaterial; particularly, a polymer or adhesive, to breakdown and beabsorbed within the physiological environment of a SI joint and/or astructure associated therewith, including sacrum and ilium bonestructures, by one or more physical, chemical, or cellular processes.

Biodegradable polymers, according to the invention, thus include,without limitation, polylactide polymers (PLA), copolymers of lactic andglycolic acids, including poly(lactic-co-glycolic) acid (PLGA) andpoly(ε-caprolactone-co-L-lactic) acid (PCL-LA); glycine/PLA co-polymers,polyethylene oxide (PEO)/PLA block copolymers, acetylated polyvinylalcohol (PVA)/polycaprolactone copolymers, poly(glycerol sebacate) (PGS)and its derivatives, including poly(glycerol-co-sebacate acrylate)(PGSA); poly(polyol sebacate) (PPS), poly(xylitol sebacate) (PXS),poly(xylitol glutamate sebacate) (PXGS), hydroxybutyrate-hydroxyvaleratecopolymers, polyesters such as, but not limited to, aspartic acid anddifferent aliphatic diols; poly(alkylene tartrates) and their copolymerswith polyurethanes, polyglutamates with various ester contents and withchemically or enzymatically degradable bonds, other biodegradablenonpeptidic polyamides, amino acid polymers, polyanhydride drug carrierssuch as, but not limited to, poly(sebacic acid) (PSA);aliphatic-aromatic homopolymers, and poly(anhydride-co-imides),poly(phosphoesters) by matrix or pendant delivery systems,poly(phosphazenes), poly(iminocarbonate), crosslinked poly(ortho ester),hydroxylated polyester-urethanes, or the like.

Biodegradable adhesives, according to the invention, thus include,without limitation, poly(glycerol-co-sebacate acrylate) (PGSA),poly(L-glutamic acid)-based compositions, poly(γ-glutamic acid)-basedcompositions, poly(alkyl cyano acrylate)-based compositions, polyacrylicacid-based compositions, including polyacrylic acid crosslinked withpentaerythritol and/or allyl sucrose, polyacrylic acid crosslinked withdivinyl glycol, and combinations thereof; fibrin-based compositions,collagen-based compositions, including collagen/poly(L-glutamic acid)compositions; albumin-based compositions, including BioGlue® (comprisespurified bovine serum albumin (BSA) and glutaraldehyde); cyanoacrylatecompositions, including butyl-2-cyanoacrylate adhesives (e.g.,Indermil®, Histoacryl®, Histoacryl® Blue, and LiquiBand®) andoctyl-2-cyanoacrylate adhesives (e.g., Dermabond®, SurgiSeal™,LiquiBand® Flex, and OctylSeal); poly(ethylene glycol) (PEG) basedcompositions, including FocalSeal®, Progel™ Duraseal™, DuraSeal™ Xact,Coseal® and ReSure Sealant; polysaccharide-based compositions,polypeptide-based compositions, and combinations thereof.

The term “osteogenic composition”, as used herein, means and includes anagent or composition that induces or modulates an osteogenicphysiological or biological process, or cellular activity, e.g., inducesproliferation, and/or growth and/or remodeling and/or regeneration ofbone or osseous tissue.

The term “osteogenic composition” thus means and includes, withoutlimitation, the following osteogenic materials and compositionscomprising same: demineralized bone matrix, autograft bone material,allograft bone material, xenograft bone material,polymethyl-methacrylate, calcium-based bone void filler material,including hydroxyapatite (HA) and tricalcium phosphate; and combinationsor mixtures thereof.

The term “osteogenic composition” also means and includes, withoutlimitation, the following polymer materials and compositions comprisingsame: poly(glycerol sebacate) (PGS), poly(glycerol-co-sebacate) acrylate(PGSA) and co-polymers, such as poly(glycerol sebacate)-co-poly(ethyleneglycol) (PGS-PEG); and/or composites thereof, e.g., PGS-hydroxyapatite(HA) composites and PGS-poly(ε-caprolactone) (PGS-PCL) composites.

The term “osteogenic composition” also means and includes, withoutlimitation, acellular extracellular matrix (ECM) derived from mammaliantissue sources.

The term “osteogenic composition” thus means and includes, withoutlimitation, acellular ECM derived from bone or osseous tissue, smallintestine submucosa (SIS), epithelium of mesodermal origin, i.e.,mesothelial tissue, placental tissue, omentum tissue, and combinationsthereof.

The terms “biologically active agent” and “biologically activecomposition” are used interchangeably herein, and mean and include agentor composition that induces or modulates a physiological or biologicalprocess, or cellular activity, e.g., induces proliferation, and/orgrowth and/or regeneration of tissue, including osseous tissue.

The terms “biologically active agent” and “biologically activecomposition”, as used herein, thus include agents and compositions thatcan be varied in kind or amount to provide a therapeutic level effectiveto mediate the formation or healing of osseous tissue, cartilage andconnective tissue, e.g., tendons and ligaments. The term “biologicallyactive composition”, in some instances, thus means and includes an“osteogenic composition.”

The terms “biologically active agent” and “biologically activecomposition” thus mean and include, without limitation, the followingbone morphogenic proteins (BMPs) and compositions comprising same:BMP-1, BMP2a, BMP2b, BMP3, BMP4, BMP5, BMP6, BMP7 (also referred to asosteogenic protein 1 (OP-1)) and BMP8a.

The terms “biologically active agent” and “biologically activecomposition” also mean and include, without limitation, the followingbiological agents and compositions comprising same: platelet derivedgrowth factor (PDGF), an insulin-like growth factor (IGF), includingIGF-1 and IGF-2; basic fibroblast growth factor (bFGF) (also referred toas FGF2), transforming growth factor-β (TGF-β), including, TGF-β1 andTGF-β2, a growth hormone (GH), parathyroid hormone (PTH, includingPTH1-34), transforming growth factor-α (TGF-α), granulocyte/macrophagecolony stimulating factor (GM-CSF), epidermal growth factor (EGF),growth and differentiation factor-5 (GDF-5), vascular endothelial growthfactor (VEGF), angiogenin, angiopoietin-1, del-1, follistatin,granulocyte colony-stimulating factor (G-CSF), hepatocyte growthfactor/scatter factor (HGF/SF), interleukin-8 (IL-8), interleukin-10(IL-10), leptin, midkine, placental growth factor, platelet-derivedendothelial cell growth factor (PD-ECGF), platelet-derived growthfactor-BB (PDGF-BB), pleiotrophin (PTN), progranulin, proliferin, amatrix metalloproteinase (MMP), angiopoietin 1 (ang1), angiopoietin 2(ang2) and delta-like ligand 4 (DLL4).

The terms “biologically active agent” and “biologically activecomposition” also mean and include, without limitation, the followingcells and compositions comprising same: bone marrow-derived progenitorcells, bone marrow stromal cells (BMSCs), osteoprogenitor cells,osteoblasts, osteocytes, osteoclasts, committed or partially committedcells from the osteogenic or chondrogenic lineage, hematopoietic stemcells, chondrocytes, chondrogenic progenitor cells (CPCs), mesenchymalstem cells (MSCs) and embryonic stem cells.

The terms “biologically active agent” and “biologically activecomposition” also mean and include an “extracellular vesicle (EV)”,“exosome”, “microsome” or “micro-vesicle”, which are usedinterchangeably herein, and mean and include a biological structureformed from a hydrocarbon monolayer or bilayer configured to contain orencase a composition of matter.

The terms “extracellular vesicle (EV)”, “exosome”, “microsome” and“micro-vesicle” thus include, without limitation, a biological structureformed from a lipid layer configured to contain or encase biologicallyactive agents and/or combinations thereof.

The terms “extracellular vesicle (EV)”, “exosome”, “microsome” and“micro-vesicle” also include, without limitation, EVs derived from theaforementioned cells and compositions comprising same, e.g.,BMSC-derived EVs.

The terms “pharmacological agent” and “active agent” are usedinterchangeably herein, and mean and include an agent, drug, compound,composition or mixture thereof, including its formulation, whichprovides some therapeutic, often beneficial, effect. This includes anyphysiologically or pharmacologically active substance (or compositioncomprising same) that produces a localized or systemic effect or effectsin animals, including warm blooded mammals.

The terms “pharmacological agent” and “active agent” thus mean andinclude, without limitation, the following osteoinductive agents andcompositions comprising same: icaritin, tumor necrosis factor alpha(TNF-α) inhibitors, including etanercept and infliximab,disease-modifying anti-rheumatic drugs (DMARDs), including methotrexateand hydroxychloroquine, antibiotics, anti-viral agents, steroidalanti-inflammatories, non-steroidal anti-inflammatories, anti-thromboticagents, including anti-coagulants and anti-platelet agents, andvasodilating agents.

The terms “pharmacological agent” and “active agent” further mean andinclude, without limitation, the following bisphosphonate agents andcompositions comprising same: risedronate (Actonel®), alendronate(Fosamax®), ibandronate (Boniva®), zoledronic acid (Reclast®),pamidronate (Aredia®) and etidronate (Didronel®).

The terms “pharmacological agent” and “active agent” further mean andinclude, without limitation, the following antibiotics and compositionscomprising same: penicillin, carboxypenicillins, such as ticarcillin;tetracyclines, such as minocycline; gentamicin, vancomycin,ciprofloxacin, amikacin, aminoglycosides, cephalosporins, clindamycin,erythromycin, fluoroquinolones, macrolides, azolides, metronidazole,trimethoprim-sulfamethoxazole, polymyxin B, oxytetracycline, tobramycin,cefazolin and rifampin.

The terms “anti-inflammatory” and “anti-inflammatory agent” are alsoused interchangeably herein, and mean and include a “pharmacologicalagent”, which, when a therapeutically effective amount is administeredto a subject, prevents or treats bodily tissue inflammation, i.e., theprotective tissue response to injury or destruction of tissues, whichserves to destroy, dilute, or wall off both the injurious agent and theinjured tissues.

Anti-inflammatory agents thus include, without limitation,dexamethasone, betamethasone, prednisone, prednisolone,methylprednisolone sodium succinate, methylprednisolone, cortisone,ketorolac, diclofenac and ibuprofen.

The terms “pharmacological agent” and “active agent” further mean andinclude, without limitation, the following metal-based antimicrobialsand compositions comprising same: silver particles, copper particles,cobalt particles, nickel particles, zinc particles, zirconium particles,molybdenum particles, lead particles and mixtures thereof.

As indicated above, the term “pharmacological composition”, as usedherein, means and includes a composition comprising a “pharmacologicalagent” and “active agent”.

The term “therapeutically effective”, as used herein, means that theamount of the “pharmacological agent” and/or “pharmacologicalcomposition” and/or “biologically active agent” and/or “biologicallyactive composition” administered is of sufficient quantity to ameliorateone or more causes, symptoms, or sequelae of a disease or disorder. Suchamelioration only requires a reduction or alteration, not necessarilyelimination, of the cause, symptom, or sequelae of a disease ordisorder.

The terms “patient” and “subject” are used interchangeably herein, andmean and include warm blooded mammals, humans and primates; avians;domestic household or farm animals, such as cats, dogs, sheep, goats,cattle, horses and pigs; laboratory animals, such as mice, rats andguinea pigs; fish; reptiles; zoo and wild animals; and the like.

The terms “one embodiment”, “one aspect”, and “an embodiment” and “anaspect”, as used herein, means that a particular feature, structure, orcharacteristic described in connection with the embodiment may beincluded in at least one embodiment and not that any particularembodiment is required to have a particular feature, structure orcharacteristic described herein unless set forth in the claim.

The phrase “in one embodiment” or similar phrases employed herein do notlimit the inclusion of a particular element of the invention to a singleembodiment. The element may thus be included in other, or allembodiments discussed herein.

The term “substantially”, as used herein, means and includes thecomplete or nearly complete extent or degree of an action,characteristic, property, state, structure, item, or result to functionas indicated. For example, an object that is “substantially” enclosedwould mean that the object is either completely enclosed or nearlycompletely enclosed. The exact allowable degree of deviation fromabsolute completeness may in some cases depend on the specific context,such that enclosing nearly all the length of a lumen would besubstantially enclosed, even if the distal end of the structureenclosing the lumen had a slit or channel formed along a portionthereof.

Use of the term “substantially” is equally applicable when used in anegative connotation to refer to the complete or near complete lack ofan action, characteristic, property, state, structure, item, or result.For example, structure which is “substantially free of” a bottom wouldeither completely lack a bottom or so nearly completely lack a bottomthat the effect would be effectively the same as if it completely lackeda bottom.

The term “comprise” and variations of the term, such as “comprising” and“comprises,” means “including, but not limited to” and is not intendedto exclude, for example, other components, elements or steps.

The following disclosure is provided to further explain in an enablingfashion the best modes of performing one or more embodiments of thepresent invention. The disclosure is further offered to enhance theunderstanding and appreciation for the inventive principles andadvantages thereof, rather than to limit in any manner the invention.The invention is defined solely by the appended claims, including anyamendments made during the pendency of this application, and allequivalents of those claims as issued.

As indicated above, the present invention is directed tominimally-invasive methods, systems and apparatus for stabilizingdysfunctional SI joints.

In some embodiments of the invention, there are thus providedminimally-invasive systems for stabilizing dysfunctional SI joints. Asindicated above, in a preferred embodiment, the minimally-invasivesystems (also referred to herein as “minimally-invasive SI jointstabilization systems”) can be readily employed in minimally-invasivemethods or procedures to stabilize dysfunctional SI joints via aposterior approach.

As indicated above, SI joint stabilization, including minimally-invasiveSI joint stabilization, typically comprises surgical placement of aprosthesis proximate to or in a dysfunctional SI joint via anterior,lateral and posterior approaches to the SI joint.

From the perspective of FIG. 1A, an anterior approach to the SI joint 6(and, hence, a dysfunctional SI joint) would be substantiallyperpendicular to the page upon which FIG. 1A is printed.

Referring now to FIG. 2A there is shown a close-up illustration of aportion of the leftmost SI joint 6 illustrated in FIG. 1A. Forillustrative simplicity, a uniform layer of cortical bone 8 is shownadjacent a deeper layer of trabecular bone 10 on both of the depictedsacrum 2 and ilium 4 portions. However, in actuality, such layers arefar less uniform and homogeneous.

Referring now to FIG. 2B, there is shown a view of the same structurefrom a different posterior perspective. From the perspective of FIG. 2B,a posterior approach to the SI joint 6 (and, hence, a dysfunctional SIjoint) would be substantially perpendicular to the page upon which FIG.2B is printed. Indeed, referring to FIG. 2C, a variation similar to thatdepicted in FIG. 2A is illustrated, showing an approximate approachvector for a lateral approach to the SI joint 6 versus a posteriorapproach, using the orientation paradigms introduced in FIGS. 1A and2A-2C. Such paradigm is used to illustrate various embodiments of thesubject invention in various figures that follow FIGS. 1A and 2A-2C.

As indicated above, a major disadvantage associated with manyconventional anterior or lateral approaches to a dysfunctional SI jointis that muscles and ligaments are typically disrupted and often damaged.Nerves and blood vessels are also susceptible to damage during such SIjoint stabilization methods.

In contrast, a posterior approach to a dysfunctional SI joint is muchless invasive. Indeed, less tissue and fewer muscles are disrupted, andnerves and large blood vessels are avoided.

As indicated above, in a preferred embodiment of the invention, thesystem for stabilizing a dysfunctional SI joint comprises a toolassembly and a prosthesis.

Referring now to FIGS. 3A-3C, 4A-4C and 5A-5B, a preferred tool assemblyof the invention will be described in detail. As illustrated in FIGS.3A-3C and 5A-5B, in a preferred embodiment, the tool assembly comprisesan elongated guide probe 20, an SI joint opening or defect creationassembly (referred to hereinafter as “defect creation assembly”) 30, andprosthesis deployment assembly 50.

Referring first to FIGS. 3A and 3B, there is shown a preferredembodiment of an elongated guide probe 20 of the invention. Asillustrated in FIGS. 3A and 3B, the elongated guide probe 20 comprisesproximal and distal ends 22, 24.

As further illustrated in FIG. 3B, and set forth in Co-pending priorityU.S. application Ser. No. 13/857,977 and Co-pending U.S. applicationSer. No. 17/463,779, filed on Sep. 1, 2021, which are expresslyincorporated by reference herein, the elongated guide probe 20 is sizedand configured to be positioned in the dysfunctional SI joint andfunction as a guide for advancing the defect creation assemblies of theinvention; particularly, defect creation assembly 30, into dysfunctionalSI joints and placement of a prosthesis therein.

Referring now to FIGS. 3B and 3C, there is shown a preferred embodimentof the defect creation assembly 30 (referred to as an“osteotome/cannulation assembly” in Co-pending priority U.S. applicationSer. No. 13/857,977).

As also set forth in Co-pending U.S. application Ser. Nos. 13/857,977and 17/463,779, the defect creation assembly 30 is configured andadapted to create pre-determined, surgically produced open spaces ordefects in the dysfunctional SI joint (referred to herein after as“pilot SI joint openings”) to accommodate placement of a prosthesis ofthe invention therein.

As illustrated in FIGS. 3B and 3C, the defect creation assembly 30comprises a housing 32, having a longitudinal axis LA₁, a proximal end34, a distal end 36, and a guide member lumen 38 that extends throughthe defect creation assembly 30.

As further illustrated in FIG. 3B, the guide member lumen 38 is adaptedto receive the guide probe 20 therein, whereby the defect creationassembly 30 is allowed to slidably translate or be advanced along theguide probe 20 to position the defect creation assembly 30 proximate toa dysfunctional SI joint site.

In a preferred embodiment of the invention, the defect creation assembly30 further comprises a bone dislodging apparatus or system 40 disposedon the defect creation assembly distal end 36, which is configured andadapted to dislodge portions of osseous tissue, i.e., bone, proximateand in the dysfunctional SI joint.

As set forth in Co-pending U.S. application Ser. No. 17/463,779, thebone dislodging system 40 can comprise various bone dislodgingapparatus, such as a drill assembly and associated drill bit ororthopedic burr, which can be operated manually, pneumatically, orelectromechanically. In a preferred embodiment, the bone dislodgingsystem 40 comprises a drill assembly and associated drill bit.

As shown in greater detail in FIG. 3C, according to the invention, thedistal end 36 of the defect creation assembly 30 may also comprise oneor more teeth or apices 42 configured to assist with creation of a pilotSI joint opening in SI joint bone structures, i.e., sacrum or ilium bonestructures.

As indicated above, in a preferred embodiment, the defect creationassemblies of the invention (and, particularly, defect creation assembly30) are configured and adapted to create pilot SI joint openings in SIjoint bone structures to accommodate placement of a prosthesis of theinvention therein.

It is however, to be understood that defect creation assembly 30described herein, is but one embodiment of a defect creation assemblythat can be employed within the scope of the invention to create pilotSI joint openings in SI joint bone structures. Indeed, as indicatedabove and discussed in detail below, various conventional apparatus andsystems, such as a surgical drill, can also be employed within the scopeof the invention to create pilot SI joint openings of the invention inSI joint bone structures.

As also set forth in Co-pending U.S. application Ser. Nos. 13/857,977and 17/463,779, the defect creation assemblies of the invention,including defect creation assembly 30, are configured and adapted tocreate pilot SI joint openings in SI joint bone structures of varioussizes and configurations. Illustrative are the pilot SI joint openingsdepicted in FIGS. 11C-11E of Co-pending priority U.S. application Ser.No. 13/857,977.

Referring now to FIG. 4A, there is shown one embodiment of a preferredpilot SI joint opening of the invention (denoted “100”) that can becreated with the defect creation assemblies of the invention;particularly, defect creation assembly 30.

As illustrated in FIG. 4A, the pilot SI joint opening 100 comprises athree-dimensional opening comprising first and second lobe regions 103,104; the first lobe region 103 being disposed in the sacrum 2 andcomprising a sacrum opening three-dimensional shape, and the second loberegion 104 being disposed in the ilium 4 and comprising an ilium openingthree-dimensional shape.

As further illustrated in FIG. 4A, the three-dimensional pilot SI jointopening 100 preferably comprises an SI joint opening cross-sectionalshape in a plane that intersects the sacrum 2 and ilium 4 bonestructures; the plane being substantially perpendicular to thelongitudinal axis LA₁ of the defect creation assembly 30 when the defectcreation assembly 30 is disposed in a defect creation position in thedysfunctional SI joint. The three-dimensional pilot SI joint openingcross-sectional shape thus comprises the sacrum openingthree-dimensional shape and ilium opening three-dimensional shape.

In some embodiments, the three-dimensional pilot SI joint opening 100 isdefined in part by at least one noncircular cross-sectional shapedregion (denoted “105”) in the noted plane.

As additionally illustrated in FIG. 4A, the three-dimensional pilot SIjoint opening 100, i.e., cross-sectional shape thereof, also defines across-sectional area of the three-dimensional pilot SI joint openingcross-sectional shape (denoted “A² _(i)- 1”).

The three-dimensional pilot SI joint opening 100, i.e., cross-sectionalshape thereof, also comprises a longitudinal axis (denoted “LA₂”) in theplane that intersects the sacrum 2 and ilium 4 and an initial pilot SIjoint opening length along the axis LA₂.

Referring now to FIG. 4B, there is shown a further pilot SI jointopening of the invention (denoted “200”) that can be created with thedefect creation assemblies of the invention; particularly, defectcreation assembly 30.

As illustrated in FIG. 4B, the pilot SI joint opening 200 comprises twothree-dimensional pilot or guide portions or regions 203, 204; the firstguide portion 203 being disposed in the sacrum 2 and the second guideportion 204 being disposed in the ilium 4.

According to the invention, the sacrum and ilium guide portions 203, 204can comprise various configurations, e.g., cross-sectional shapes, andsizes to, as discussed in detail below, accommodate insertion of definedregions of a prosthesis of the invention therein and transition of thesacrum and ilium guide portions 203, 204 from pilot or firstconfigurations and sizes to expanded second configurations and sizeswhen the prosthesis is inserted therein.

As set forth in Co-pending U.S. application Ser. No. 17/463,779, thesacrum and ilium guide portions 203, 204 can also be disposed at variouslocations in the sacrum 2 and ilium 4, such as shown in FIGS. 4A, 4B and4C.

As illustrated in FIG. 4B, in a preferred embodiment, the sacrum andilium guide portions 203, 204 of the pilot SI joint opening 200 createdby the defect creation assembly 30 of the invention comprisesubstantially circular cross-sectional shapes.

As further illustrated in FIG. 4B, the sacrum and ilium guide portions203, 204 of the pilot SI joint opening 200, i.e., cross-sectional shapethereof, define cross-sectional areas of the sacrum and ilium guideportions 203, 204 (denoted “A² _(i)-2” and “A² _(i)-3”, respectively).

In a preferred embodiment, the sacrum and ilium guide portions 203, 204of the pilot SI joint opening 200 are disposed on a plane that similarlyintersects the sacrum 2 and ilium 4.

Referring now to FIGS. 5A-5G, there is shown a preferred embodiment of aprosthesis deployment assembly of the invention (denoted “50” in FIG.5G).

As also set forth in Co-pending U.S. application Ser. No. 17/463,779, ina preferred embodiment, the prosthesis deployment assembly 50 comprisesprosthesis engagement means configured and adapted to connect theprosthesis deployment assembly 50 to prostheses of the invention(prosthesis 70 shown in FIG. 5G) and guide the prostheses into pilot SIjoint openings created by the defect creation assembly 30.

As illustrated in FIGS. 5A-5C, the prosthesis deployment assembly 50comprises an elongated guide member 51 comprising proximal and distalends 52, 54.

As further illustrated in FIGS. 5B and 5E, the elongated guide member 51further comprises a prosthesis guide pin 56 that extends from the guidemember distal end 54. As discussed in detail below and shown in FIG. 5G,the prosthesis guide pin 56 is sized and configured to seat in aninternal prosthesis engagement member lumen 86 a or 86 b of thepreferred prosthesis 70 of the invention.

As illustrated in FIGS. 5A, 5D and 5E, the elongated guide member 51further comprises an internal lumen 58 that extends from the proximalend 52 of the elongated guide member 51 to the distal end 54 of theelongated guide member 51.

As illustrated in FIG. 5G, in a preferred embodiment of the invention,the internal lumen 58 is sized and configured to receive the prosthesisengagement rod 60 (i.e., prosthesis engagement means) of the prosthesisdeployment assembly 50, discussed below.

Referring now to FIG. 5F, there is shown a preferred embodiment of aprosthesis engagement rod 60 of the invention. As illustrated in FIG.5F, the prosthesis engagement rod 60 comprises a proximal end 62 and athreaded distal end 64, which, as discussed in detail below, is sizedand configured to threadably engage an internal prosthesis engagementmember lumen of a prosthesis of the invention, e.g., internal prosthesisengagement member lumens 86 a and/or 86 b of prosthesis 70.

As further illustrated in FIG. 5F, in a preferred embodiment, theproximal end 62 of the prosthesis engagement rod 60 comprises a knurledconfiguration to facilitate threading the prosthesis engagement rod 60into an internal prosthesis engagement member lumen of a prosthesis ofthe invention.

Referring back to FIGS. 5A and 5B, to further facilitate threading theprosthesis engagement rod 60 into an internal prosthesis engagementmember lumen of a prosthesis of the invention, in a preferredembodiment, the elongated guide member 51 further comprises an accessport 57 that provides access to the knurled proximal end 62 of theprosthesis engagement rod 60 when positioned in the internal lumen 58 ofthe elongated guide member 51, as shown in FIG. 5G.

According to the invention, the system for stabilizing dysfunctional SIjoints can comprise various prostheses, which are configured and adaptedto be inserted into pilot SI joint openings created by a defect creationassembly of the invention.

Suitable prostheses that are configured and adapted to be inserted intoa pilot SI joint opening created by a defect creation assembly of theinvention are set forth in Co-pending priority application Ser. Nos.13/857,977 and 17/463,779, which is expressly incorporated by referenceherein.

According to the invention, the prostheses illustrated in FIGS. 12A-12C,13A-13B, 14A-14C and 15A-15D of Co-pending priority application Ser. No.13/857,977 are suitable for insertion into pilot SI joint openings ofthe invention (i.e., SI joint openings 100, 200 described above) in a SIjoint, and into and through articular cartilage and cortical bone (andtrabecular bone), which define the SI joint.

Referring now to FIGS. 6A-6I, there is shown a preferred prosthesis 70of the invention, which is particularly suitable for placement in pilotSI joint openings of the invention (particularly, pilot SI jointopenings 100 and 200) in a SI joint, and into and through articularcartilage and bone structures (i.e., cortical and trabecular bone),which define the SI joint.

As illustrated in FIGS. 6A, 6E and 6F, the prosthesis 70 comprises abiocompatible and, hence, implantable member comprising proximal anddistal ends 72, 74, and first and second elongated partially cylindricalsections 76 a, 76 b connected to a bridge section 78, whereby theprosthesis 70 comprises a continuous exterior surface comprising firstand second partially cylindrical surface regions 77 a, 77 b.

As further illustrated in FIGS. 6A, 6E and 6F, the first and secondpartially cylindrical sections 76 a, 76 b comprise proximal and distalends 79 a, 79 b. The bridge section 78 similarly comprises proximal anddistal ends 81 a, 81 b.

According to the invention, the prosthesis 70 can comprise any suitablelength from the proximal ends 79 a to the distal ends 79 b of thepartially cylindrical sections 76 a, 76 b. In some embodiments, theprosthesis 70 comprises a length in the range of 20-50 mm, morepreferably, a length in the range of 30-40 mm.

As illustrated in FIGS. 6C, 6E, and 6F, and FIGS. 4A and 4B, the firstpartially cylindrical surface region 77 a preferably comprises apartially cylindrical surface region shape that corresponds to at leasta portion of the first lobe region 103 of the pilot SI joint opening 100and/or the sacrum guide portion 203 of the pilot SI joint opening 200,and/or the second lobe region 104 of the pilot SI joint opening 100and/or the ilium guide portion 204 of the pilot SI joint opening 200,depending on the entry position of the prosthesis 70 into the pilot SIjoint openings 100, 200.

The second partially cylindrical surface region 77 b similarlypreferably comprises a partially cylindrical surface region shape thatcorresponds to at least a portion of the first lobe region 103 of thepilot SI joint opening 100 and/or the sacrum guide portion 203 of thepilot SI joint opening 200, or the second lobe region 104 of the pilotSI joint opening 100 and/or the ilium guide portion 204 of the pilot SIjoint opening 200, again depending on the entry position of theprosthesis 70 into the pilot SI joint openings 100, 200.

As illustrated in FIGS. 6A, 6B, and 6F-6H, the distal end 81 b of thebridge section 78 preferably comprises a taper region 82, which isconfigured and adapted to disrupt, i.e., cut into and through, articularcartilage and cortical bone 8 (and, in some aspects, trabecular bone10), which define a SI joint.

According to the invention, the taper region 82 of the bridge section 78can comprise various configurations including, without limitation,X-bevel, wedge-shaped or bevel, including top and bottom wedge bevels,Y-bevel, including top and bottom Y-bevels, and K-bevel configurations.

In some embodiments of the invention, the taper region 82 comprises twoangled regions that intersect at a central point 83, i.e., pointedproximate the mid-region of the bridge section 78, such as shown inFIGS. 6A and 6F. In some embodiments, the taper region 82 comprises asingle angled or sloped region defining a plane that intersects theplane defined by the bottom surface of the prosthesis 70, i.e., wedgeshaped or bevel configuration.

In a preferred embodiment, the distal ends 79 b of the first and secondelongated partially cylindrical sections 76 a, 76 b also comprisetapered regions 84 a, 84 b, which facilitate (i) insertion of the distalends 79 b of the first and second elongated partially cylindricalsections 76 a, 76 b into the first and second lobe regions 103, 104 ofthe pilot SI joint opening 100 and/or the sacrum and ilium guideportions 203, 204 of the pilot SI joint opening 200, and (ii) asdiscussed in detail below, in some embodiments, transition of the pilotSI joint opening 100 from a first configuration and size (and, hence,cross-sectional area, i.e., A² _(i)-1 shown in FIG. 4A) to a secondexpanded configuration and size (and, hence, cross-sectional area, i.e.,A²-4 shown in FIG. 8A) when the prosthesis 70 is inserted therein, andtransition of the sacrum and ilium guide portions 203, 204 of pilot SIopening 200 from first configurations and sizes (and, hence,cross-sectional areas, i.e., A² _(i)-2 and A² _(i)-3 shown in FIG. 4B)to expanded second configurations and sizes (and, hence, cross-sectionalareas, i.e., A²-5 and A²-6 shown in FIG. 8B) when the prosthesis 70 isinserted therein.

As illustrated in FIGS. 6C, 6E, and 6H, the first elongated partiallycylindrical section 76 a of the prosthesis 70 comprises an internalprosthesis engagement member lumen 86 a that extends from the proximalend 79 a of the first elongated partially cylindrical section 76 a.

As illustrated in FIGS. 6C and 6E, the second elongated partiallycylindrical section 76 b of the prosthesis 70 also comprises an internalprosthesis engagement member lumen 86 b that extends from the proximalend 79 a of the second elongated partially cylindrical section 76 b.

In a preferred embodiment, the internal prosthesis engagement memberlumens 86 a, 86 b of the prosthesis 70 are sized and configured toreceive the prosthesis guide pin 56 of the prosthesis deploymentassembly 50 and, as discussed below, the prosthesis engagement rod 60 ofthe prosthesis deployment assembly 50.

As set forth in Co-pending U.S. application Ser. No. 17/463,779 andillustrated in FIGS. 6E and 6G, in a preferred embodiment, the internalprosthesis engagement member lumens 86 a, 86 b of the first and secondelongated partially cylindrical sections 76 a, 76 b comprise a threadedregion 87 proximate the proximal end 79 a that is sized and configuredto receive and threadably engage the threaded distal end 64 of theprosthesis engagement rod 60 of the prosthesis deployment assembly 50and, as discussed in detail below, the prosthesis extraction rods orscrews 602 a, 602 b of the prosthesis extraction assembly 600.

In a preferred embodiment, the internal prosthesis engagement lumens 86a, 86 b are also configured to receive agents and compositions thatfurther facilitate adhesion of the prosthesis 70 to the pilot SIopenings 100, 200 of the invention and, thereby, sacrum and/or iliumbone structures, and the aforementioned biologically active agents andcompositions, including osteogenic agents and compositions, andpharmacological agents and compositions that facilitate osseous or bonetissue ingrowth into the prosthesis 70 and healing of the SI joint bonestructures.

Referring back to FIGS. 6A and 6B, in a preferred embodiment, theprosthesis 70 further comprises a plurality of slots 90 and holes 92,which preferably are in communication with the internal prosthesisengagement member lumens 86 a, 86 b.

In a preferred embodiment, the agents and compositions referenced aboveare adapted to extrude through the slots 90 and holes 92 of theprosthesis 70 when the prosthesis 70 is inserted in a pilot SI jointopening (i.e., pilot SI joint openings 100 or 200), to, as indicatedabove, (i) further facilitate adhesion of the prosthesis 70 to the pilotSI openings 100, 200 of the invention and, thereby, sacrum and/or ilium,and (ii) facilitate osseous or bone tissue ingrowth into the prosthesis70 and healing of the SI joint bone structures.

Referring now to FIG. 6I, according to the invention, the continuousexterior surface of the prosthesis 70, which is illustrated in FIGS. 6Cand 6D, defines a prosthesis cross-sectional shape (denoted “P_(CSS)”)having a longitudinal axis LA₃.

According to one embodiment of the invention, the length of theprosthesis cross-sectional shape P_(CCS) along longitudinal axis LA₃ isgreater than the length of the pilot SI joint opening 100, i.e.,cross-sectional shape thereof illustrated in FIG. 4A, along thelongitudinal axis LA₂ thereof, whereby, when the prosthesis 70 isinserted into pilot SI joint opening 100, as illustrated in FIG. 7A, thepilot SI opening 100 transitions to a post-prosthesis insertion SI jointopening 300 comprising a larger cross-sectional length shape thatcorresponds to the length of the prosthesis cross-sectional shapeP_(CCS).

As illustrated in FIG. 8A, in a preferred embodiment, when theprosthesis 70 is inserted into pilot SI joint opening 100, thecross-sectional area of the post-prosthesis insertion SI joint opening300 also comprises a cross-sectional area (denoted “A²-4”) that isgreater than the cross-sectional area A² _(i)-1 of the pilot SI jointopening 100.

As further illustrated in FIG. 8A, the noncircular region 105 of pilotSI joint opening 100 also transitions to a much larger noncircularregion (denoted “305”), which is achieved by virtue of the taperedbridge section 78 of the prosthesis 70 cutting into and through thearticular cartilage and cortical bone 8, which define the SI joint 6,and the trabecular bone 10 proximate the SI joint 6.

According to the embodiment of the invention, when the prosthesis 70 isinserted into pilot SI joint opening 200, as illustrated in FIG. 7B, thepilot SI joint opening 200 similarly transitions to a post-prosthesisinsertion SI joint opening 400, wherein, as illustrated in FIG. 8B, thecross-sectional areas of the post-prosthesis sacrum and ilium guideportions of the post-prosthesis insertion SI joint opening 400 (nowdenoted “402” and “404”, respectively) comprise greater cross-sectionalareas (denoted “A²-5” and “A²-6”).

As further illustrated in FIG. 8B, the post-prosthesis insertion SIjoint opening 400 also comprises a noncircular region (denoted “405”),which is similarly achieved by virtue of the tapered bridge section 78of the prosthesis 70 cutting into and through the articular cartilageand cortical bone 8, which define the SI joint 6, and the trabecularbone 10 proximate the SI joint 6.

As illustrated in FIGS. 6I, 8A and 8B, the post-prosthesis insertion SIjoint openings 300, 400 also comprise cross-sectional shapes thatcorrespond to the prosthesis cross-sectional shape “P_(CSS)” defined bythe outer surface of the prosthesis 70, including the first and secondelongated partially cylindrical sections 76 a, 76 b and bridge section78.

In a preferred embodiment of the invention, to achieve sufficientexpansion of the pilot SI joint openings 100, 200 when the prosthesis 70is inserted therein, preferably, the cross-sectional areas of theregions defined by the first and second elongated partially cylindricalsections 76 a, 76 b of the prosthesis 70 are at least 0.05% greater thanthe cross-sectional areas defined by the first and second lobe regions103, 104 of the pilot SI joint opening 100, and the cross-sectionalareas defined by the sacrum and ilium guide portions 203, 204 of pilotSI joint opening 200.

In some embodiments of the invention, the cross-sectional areas of theregions defined by the first and second elongated partially cylindricalsections 76 a, 76 b of the prosthesis 70 are substantially equal to orslightly smaller, e.g., ≤0.05%, than the cross-sectional areas definedby the first and second lobe regions 103, 104 of the pilot SI jointopening 100, and the cross-sectional areas defined by the sacrum andilium guide portions 203, 204 of pilot SI joint opening 200.

According to the invention, the prosthesis 70, as well as the prosthesesdisclosed in Co-pending priority application Ser. No. 13/857,977, cancomprise various biocompatible materials, including metals and metalalloys, such as titanium, stainless-steel, cobalt-chromium alloys, andnickel-titanium alloys.

The prosthesis 70, as well as the prostheses disclosed in Co-pendingpriority application Ser. No. 13/857,977, can also comprise variousbiocompatible polymers, including, without limitation, reinforcedpolymers, such as carbon fiber reinforced polymers and metal-framedpolymers.

According to the invention, the prosthesis 70, as well as the prosthesesdisclosed in Co-pending priority application Ser. No. 13/857,977, canalso comprise a porous structure to facilitate (i) adhesion of theprosthesis 70 to a post-prosthesis insertion SI joint opening of theinvention; particularly, post-prosthesis insertion SI joint openings300, 400 and, thereby, to SI joint bone structures, i.e., sacrum andilium bone structures, and (ii) bone or osseous tissue ingrowth into theprosthesis 70.

According to the invention, the prosthesis 70, as well as the prosthesesdisclosed in Co-pending priority application Ser. No. 13/857,977, canalso comprise various exterior surface textures and roughness tofacilitate or enhance engagement of the prosthesis to a post-prosthesisinsertion SI joint opening, such as post-prosthesis insertion SI jointopenings 300, 400, and, thereby, to SI joint bone structures, i.e.,sacrum and ilium bone structures, and/or maintain engagement thereto andpositioning therein. The surface of the prosthesis 70 (as well as theprostheses disclosed in Co-pending priority application Ser. No.13/857,977) can, thus, comprise a roughness grade number of N1(Ra=˜0.025 μm), N2 (Ra=˜0.05 μm), N3 (Ra=˜0.1 μm), N4 (Ra=˜0.2 μm), N5(Ra=˜0.4 μm), N6 (Ra=˜0.08 μm), N7 (Ra=˜1.6 μm), N8 (Ra=˜3.2 μm), N9(Ra=˜6.3 μm), N10 (Ra=˜12.5 μm), N11 (Ra=™25 μm) or N12 (Ra=˜50 μm).

In some embodiments of the invention, the prosthesis 70, as well as theprostheses disclosed in Co-pending priority application Ser. No.13/857,977, further comprise an outer coating.

In some embodiments, the outer coating comprises a biocompatible and,preferably, biodegradable adhesive composition. According to theinvention, suitable adhesive compositions include, without limitation,poly(L-glutamic acid)-based compositions, poly(γ-glutamic acid)-basedcompositions, poly(alkyl cyano acrylate)-based compositions, polyacrylicacid-based compositions, including polyacrylic acid crosslinked withpentaerythritol and/or allyl sucrose, polyacrylic acid crosslinked withdivinyl glycol and combinations thereof; fibrin-based compositions,collagen-based compositions, including collagen and poly(L-glutamicacid) compositions; albumin-based compositions, including BioGlue®(comprises purified bovine serum albumin (BSA) and glutaraldehyde);cyanoacrylate compositions, including butyl-2-cyanoacrylate adhesives(e.g., Indermil®, Histoacryl®, Histoacryl® Blue, and LiquiBand®) andoctyl-2-cyanoacrylate adhesives (e.g., Dermabond®, SurgiSeal™,LiquiBand® Flex, and OctylSeal); poly(ethylene glycol) (PEG) basedcompositions, including FocalSeal®, Progel™ Duraseal™, DuraSeal™ Xact,Coseal® and ReSure Sealant; polysaccharide-based compositions,polypeptide-based compositions, and radiation curable materials, such aspoly(glycerol-co-sebacate) acrylate (PGSA), discussed below.

In some embodiments, the outer coating comprises a biologically activecomposition comprising one of the aforementioned biologically activeagents (referred to generally as fixation catalysts in Co-pendingpriority application Ser. No. 13/857,977) or a pharmacologicalcomposition comprising one of the forementioned pharmacological agents.

In some embodiments, the outer coating comprises one of theaforementioned polymers and/or compositions comprising same.

In some embodiments, the aforementioned polymer compositions compriseone or more of the aforementioned biologically active agents orpharmacological agents.

In some embodiments of the invention, the polymer comprisespoly(glycerol sebacate) (PGS) or a derivative thereof, including,without limitation, poly(glycerol-co-sebacate) acrylate (PGSA) and PGSco-polymers, such as poly(glycerol sebacate)-co-poly(ethylene glycol)(PGS-PEG); and/or composites thereof, e.g., PGS-hydroxyapatite (HA)composites and PGS-poly(ε-caprolactone) (PGS-PCL) composites, andcompositions comprising same.

As set forth in Co-pending U.S. application Ser. No. 17/463,779, PGS andderivatives thereof possess a unique property of inducing remodeling ofdamaged osseous or bone tissue, such as at pilot SI joint openings, and,hence, healing of the associated bone structures when disposed proximatethereto.

As set forth in Loh, et al., Poly(glycerol sebacate) Biomaterial:Synthesis and Biomedical Applications, Journal of Materials Chemistry B,vol. 3(39), pp. 7641-7652 (2015) and indicated in Table 1 below, afurther seminal property of PGS is that its physical state can bemodulated during synthesis by controlling the “degree of esterification”via at least one crosslinking agent, e.g., methylene diphenyldiisocyanate (MDI).

TABLE 1 Degree of Esterification Physical State ≤46% Solid (Brittle Wax)~47%-64% Semi-Solid (Soft Wax) ~65%-75% Viscous Liquid ~76%-83% StickyElastomer ≥84% Elastomer

According to the invention, any suitable degree of esterification of PGScan be employed for PGS when employed in or for PGS based outer coatings(i.e., polymer compositions comprising PGS) and biologically activeagent compositions of the invention.

In some embodiments, the PGS based outer coatings comprise a degree ofesterification in the range of ˜76%-83%, whereby the PGS exhibitsadhesive properties, which will enhance engagement of prosthesis 70 (aswell as the prostheses disclosed in Co-pending priority application Ser.No. 13/857,977) to the post-prosthesis insertion SI joint openings 300,400 and, thereby, to the SI joint bone structures, i.e., sacrum andilium bone structures.

As is well established, the physical state of poly(glycerol-co-sebacate)acrylate (PGSA) can also be modulated by combining the PGSA with asuitable photoinitiator and subjecting the PGSA to radiation.

Indeed, as set forth in Nij st, et al., Synthesis and Characterizationof Photocurable Elastomers from Poly(Glycerol-Co-Sebacate),Biomacromolecules, vol. 8, no. 10, pp. 3067-3073 (2007), PGSA can beinduced to transition from a liquid or flowable state to a solidelastomer state when combined with a photoinitiator, such as2-hydroxy-1-[4-hydroxyethoxy) phenyl]-2-methyl-1-propanone (D 2959, CibaGeigy), 2,2-dimethoxy-2-phenylacetophenone, titanocenes, fluorinateddiaryltitanocenes, iron arene complexes, manganese decacarbonyl andmethylcyclopentadienyl manganese tricarbonyl, and subjected toradiation, such as visible light; particularly, radiation in the rangeof approximately 380-750 nm, and ultraviolet (UV) light, particularly,radiation in the range of 10-400 nm.

Thus, in some embodiments, a composition comprising PGSA (also referredto herein as a “PGSA based composition” and “fixation composition”) isemployed to enhance the engagement of the prosthesis 70 to apost-prosthesis insertion SI joint opening, such as post-prosthesisinsertion SI joint openings 300, 400, and, thereby, SI joint bonestructures, i.e., sacrum and ilium bone structures.

In such embodiments, the PGSA based composition (in a flowable state) isdisposed in the internal prosthesis engagement member lumens 86 a, 86 bof the prosthesis 70, whereby the PGSA based composition is dispersedwhen the prosthesis 70 is positioned in the dysfunctional SI joint andfills any gaps between the prosthesis 70 and a post-prosthesis insertionSI joint opening of the invention; particularly, post-prosthesisinsertion SI joint openings 300, 400, and thereafter cured via radiationand solidified, whereby the solidified PGSA enhances the engagement ofthe prosthesis 70 to the post-prosthesis insertion SI joint opening and,thereby, to the sacrum and ilium bone structures.

PGS and its derivatives; particularly, PGSA are also excellent platformsfor delivery and, hence, administration of biologically active agentsand pharmacological agents to mammalian tissue, including osseous orbone tissue.

Thus, in some embodiments of the invention, the PGS based outer coatingsand PGS and PGSA based compositions further comprise one or more of theaforementioned biologically active or pharmacological agents.

As indicated above, in some embodiments of the invention, the system forstabilizing dysfunctional SI joints further comprises an image captureapparatus configured and adapted to capture images reflecting positionsand/or orientations of the elongated guide probe and/or defect creationassembly when disposed in the body, and, particularly, duringadvancement of the elongated guide probe and defect creation assemblytoward and into the dysfunctional SI joint.

According to the invention, suitable image capture apparatus comprise afluoroscope, a CT system, an ultrasound system, a radiography system,and a magnetic resonance imaging system.

As also indicated above, in some embodiments of the invention, thesystem for stabilizing dysfunctional SI joints further comprises a drillguide assembly that facilitates proper placement of (i) the elongatedguide probe 20 in the dysfunctional SI joint, and (ii) the pilot SIjoint openings 100, 200 of the invention and, hence, sacrum and iliumportions thereof, and, thereby, placement of the prosthesis 70 (andother prostheses described in Co-pending U.S. application Ser. No.13/857,977) in the dysfunctional SI joint.

Referring now to FIG. 9A, there is shown a preferred embodiment of adrill guide assembly 500 of the invention.

As illustrated in FIG. 9A, the drill guide assembly 500 comprises anaccess sleeve 502, drill guide 520 and a guide pin 530.

Referring now to FIGS. 9B-9D, there is shown a preferred embodiment ofthe access sleeve 502.

As illustrated in FIGS. 9B-9D, the access sleeve 502 comprises proximaland distal ends 504 a, 504 b, and an internal opening 506 that extendsfrom the proximal end 504 a to the distal end 504 b of the access sleeve502, and a plurality of lumens 507, which, as illustrated in FIG. 9A,are sized and configured to receive and position Kirschner wires(K-wires) 509 or similar pin structures therein.

As illustrated in FIG. 9A, in a preferred embodiment, the access sleeveinternal opening 506 is sized and configured to receive and position thedrill guide 520 therein.

As further illustrated in FIGS. 9B and 9D, the proximal end 504 a of theaccess sleeve 502 comprises a planar region 503, which, as illustratedin FIG. 9A, is configured to seat the proximal end 522 a of the drillguide 520 (discussed below) thereon.

In a preferred embodiment, as additionally shown in FIGS. 9B and 9D, theproximal end 504 a of the access sleeve 502, i.e., planar region 503,further comprises two (2) threaded holes 505 a, 505 b, which arepreferably disposed on opposing edge regions of the planar region 503.According to the invention, the threaded holes 505 a, 505 b are sizedand configured to receive the threaded end 514 of the access sleevehandle 510, discussed below.

Referring now to FIGS. 9E and 9F, there is shown a preferred embodimentof the access sleeve handle 510.

As illustrated in FIGS. 9E and 9F, the access sleeve handle 510preferably comprises an elongated cylindrical shaped member comprisingproximal and distal ends 512 a, 512 b.

As further illustrated in FIG. 9E, in a preferred embodiment, the distalend 512 b of the access sleeve handle 510 comprises a threaded extension514 that is sized and configured to cooperate with the threaded holes505 a, 505 b of the access sleeve 502, whereby the access sleeve handle510 can be threadably engaged to the access sleeve 502.

Referring now to FIGS. 9G-9J, there is shown a preferred embodiment ofthe drill guide 520.

As illustrated in FIGS. 9G-9J, the drill guide 520 comprises proximaland distal ends 522 a, 522 b, a pair of drill guide lumens 524 a, 524 band a drill guide medial lumen 526; the drill guide lumens 524 a, 524 band drill guide medial lumen 526 extending from the proximal end 522 ato the distal end 522 b of the drill guide 520.

As illustrated in FIG. 9A, in a preferred embodiment, the drill guidelumens 524 a, 524 b are sized and configured to receive (i) a bonedislodging system 40 of the defect creation assembly 30, in thisinstance, the drill bit 41 shown in FIG. 9L, and (ii) the guide pin 530shown in FIG. 9K and discussed below.

In a preferred embodiment, the drill guide medial lumen 526 is sized andconfigured to receive and guide the elongated guide probe 20 of theinvention to a desired position proximate the dysfunctional SI joint.

According to the invention, the drill guide internal lumens 524 a, 524 band drill guide medial lumen 526 can also be sized and configured toreceive various other suitable instruments, such as surgical scopes,center punches, location pins, drill probes and drill stop assemblies,to facilitate the creation of a pilot SI joint opening.

Referring back to FIGS. 9G and 9H, in a preferred embodiment, theproximal end 522 a of the drill guide 520 comprises a planarconfiguration comprising an extended region 523, which, as illustratedin FIG. 9A, is sized and configured to abut the proximal end 504 a ofthe access sleeve 502 to position the drill guide 520 therein.

Referring now to FIG. 9K, there is shown one embodiment of a guide pin530 of the invention.

As illustrated in FIG. 9K, the guide pin 530 preferably comprises anelongated guide member 532 comprising proximal and distal ends 534 a,534 b. The guide pin 530 further comprises a handle 536 that isoperatively connected to the proximal end 534 a of the guide member 532.

As further indicated above, in some embodiments, the system forstabilizing dysfunctional SI joints further comprises a prosthesisextraction assembly 600 that is configured and adapted to remove theprosthesis 70 from the expanded post-prosthesis insertion SI jointopening and, thereby, dysfunctional SI joint.

Referring now to FIGS. 10A-10G, there is shown a preferred embodiment ofa prosthesis extraction assembly 600 of the invention with prosthesis 70connected thereto.

As illustrated in FIG. 10A, the prosthesis extraction assembly 600generally comprises prosthesis extraction rods or screws 602 a, 602 b,an extraction fork 610 and a slap hammer assembly 620.

As illustrated in FIG. 10A-10C, the prosthesis extraction rods 602 a,602 b comprise elongated rod members 605 comprising capped proximal ends604 a and threaded distal ends 604 b, which are sized and configured tothreadably engage threaded internal prosthesis engagement lumens 86 a,86 b of the prosthesis 70.

As illustrated in FIGS. 10D-10F, the extraction fork 610 comprisesproximal and distal ends 614 a, 614 b, a primary recess 612 andsecondary recesses 615 proximate the distal end 614 b. The extractionfork 610 further comprises a threaded lumen 616 proximate the proximalend 614 a, which, as discussed below, is sized and configured tothreadably engage the threaded distal end 624 b of the elongated rodmember 621 of the slap hammer assembly 620 discussed below.

As illustrated in FIG. 10A, in a preferred embodiment, the secondaryrecesses 615 of the extraction fork 610 are configured to receive andreleasably engage or ensnare the capped proximal ends 604 a of theprosthesis extraction rods 602 a, 602 b.

As further illustrated in FIG. 10A, the extraction fork 610 is furtherconfigured to releasably engage the threaded distal end 624 b of theslap hammer assembly 620 via the threaded lumen 616.

As illustrated in FIGS. 10A and 10G, the slap hammer assembly 620comprises a handle 622, an elongated rod member 621, a weighted sleevemember 626 and a bump stop 628.

As illustrated in FIG. 10G, the elongated rod member 621 comprises aproximal end 624 a, comprising internal threads 625, and a threadeddistal end 624 b.

As further illustrated in FIG. 10G, the handle 622 comprises threadeddistal end 623, which, as illustrated in FIG. 10A, is sized andconfigured to threadably engage the proximal end 624 a of the elongatedrod member 621.

As illustrated in FIG. 10A, the threaded distal end 623 of the handle622 is further sized and configured to receive and seat the bump stop628 thereon, wherein the bump stop 628 is securely positioned betweenthe handle 622 and elongated rod member 621 when the handle 622 isengaged to the elongated rod member 621.

In a preferred embodiment, the weighted sleeve member 626 is configuredto slidably translate along the elongated rod member 621 and abut theproximal end 614 a of the extraction fork 610 and bump stop 628 when theslap hammer assembly 620 is releasably engaged to the extraction fork610.

According to the invention, removal of prosthesis 70 from the expandedpost-prosthesis insertion SI joint opening is achieved as follows:

-   -   the prosthesis extraction rods 602 a, 602 b are initially        connected to prosthesis 70; and    -   after the prosthesis extraction rods 602 a, 602 b are connected        to prosthesis 70, the surgeon grips the handle 622 of the        prosthesis extraction assembly 600 and forcibly abuts the handle        622 against the bump stop 628, wherein a removal or extraction        force is exerted on prosthesis 70 via the prosthesis extraction        rods 602 a, 602 b and the prosthesis 70 is released from the        expanded post-prosthesis insertion SI joint opening.

Examples

The following example is provided to enable those skilled in the art tomore clearly understand and practice the present invention. The exampleshould not be considered as limiting the scope of the invention, butmerely as being illustrated as representative thereof.

An adult male, age 42 presented with a traumatic injury proximate the SIjoint, resulting in a dysfunctional SI joint and significant painassociated therewith, i.e., a visual analog pain score (VAS) ofapproximately 8.0.

A CT scan was initially performed to determine the full extent of thepatient's injury, check for any SI joint abnormalities and plan thestabilization procedure, including the prosthesis structure required tostabilize the dysfunctional SI joint.

The stabilization procedure was performed in accord with the method setforth in Co-pending U.S. application Ser. No. 17/463,779; specifically,¶¶ [000254]-[000262] thereof. The specifics of the procedure were asfollows:

Prosthesis

The prothesis selected for the procedure was similar to prosthesis 70illustrated in FIGS. 6A-6H and described in detail above. The prosthesiscomprised a length of 30 mm and the elongated partially cylindricalsections, i.e., barrels, of the prosthesis comprised a diameter of 7.5mm. The prosthesis was sourced from Applicant, i.e., Tenon Medical,Inc., and referred to as a CATAMARAN SIJ Fixation System™.

The prosthesis included a bone graft material, which was placed in thebarrels of the prosthesis after the prosthesis was implanted in thedysfunctional SI joint.

Posterior Inferior Surgical Approach

The initial incision was placed along the lateral lip of the posteriorthird of the iliac crest to the posterior superior spine, which provideda prosthesis entry point into the dysfunctional SI joint through theposterior ligaments at approximately the S3 level. The trajectory of theprosthesis was toward the mid-point of the 51 end plate and the sacralpromontory.

Creation of Pilot SI Joint Opening

The pilot SI joint opening was created with the defect creation assemblyshown in FIGS. 3B and 3C, and described above. The bone dislodgingapparatus of the assembly comprised a drill assembly and associateddrill bit.

The pilot SI joint opening was similar to pilot SI joint opening 200described above. The pilot SI joint opening was created by drilling afirst opening in the sacrum bone structure and a second opening in theilium bone structure (such as shown in FIG. 4B) with the drill assembly.

Radiological Assessment

CT scan images of the patient's SI joint six (6) months after the SIjoint stabilization procedure, which are shown in FIGS. 11A and 11B,reflect (i) secure and proper placement of the prosthesis in the SIjoint, (ii) substantial solid bridging of osseous tissue, and, hence,bone across the SI joint and, (iii) substantial ossification around theprosthesis.

Post-Procedure SI Joint Pain Relief and Function

After a recovery period of fourteen (14) days, the patient reported thatthe pain had been substantially reduced. Indeed, as shown in FIG. 12 ,fourteen (14) days after the procedure a visual analog pain score (VAS)of 1.8 was achieved.

The patient was also subjected to a series of post procedure tests todetermine the stability of the SI joint and mobility of themusculoskeletal structures of the pelvic and lumbar regions proximatethe SI joint. The results were very favorable. The patient testedpositive to the flexion abduction and external rotation (FABER) test.The patient also responded very favorably to Gaenslen, thigh thrust,compression and distraction tests.

The tests thus confirmed that the post procedure SI joint was stabilizedand that the musculoskeletal structures of the pelvic and lumbar regionsproximate thereto were restored to a near normal level.

As will readily be appreciated by one having ordinary skill in the art,the present invention provides numerous advantages compared to prior artmethods and apparatus for stabilizing dysfunctional SI joints. Among theadvantages are the following:

-   -   the provision of improved SI joint stabilization systems and        apparatus, which can be readily employed in minimally-invasive        SI joint stabilization procedures to stabilize dysfunctional SI        joints via a posterior approach;    -   the provision of improved SI joint prostheses, which, when        implanted in a dysfunctional SI joint, effectively ameliorate        pain associated with the SI joint dysfunction;    -   the provision of improved SI joint prostheses, which can readily        be employed in minimally-invasive SI joint stabilization        procedures and provide secure engagement to SI joint structures;    -   the provision of improved SI joint prostheses, which can readily        be employed in minimally-invasive SI joint stabilization        procedures and possess optimal structural properties to        effectively stabilize dysfunctional SI joints; and    -   the provision of improved SI joint prostheses, which can readily        be employed in minimally-invasive SI joint stabilization methods        and facilitate remodeling of damaged osseous tissue and        regeneration of new osseous tissue and osseous tissue        structures.

Without departing from the spirit and scope of this invention, one ofordinary skill can make various changes and modifications to theinvention to adapt it to various usages and conditions. As such, thesechanges and modifications are properly, equitably, and intended to be,within the full range of equivalence of the following claims.

What is claimed is:
 1. A sacroiliac (SI) joint stabilization prosthesis,comprising: an elongated prosthesis structure adapted to be implanted ina dysfunctional SI joint via a posterior approach, said dysfunctional SIjoint being disposed between and defined by a sacrum bone structure andan ilium bone structure, said elongated prosthesis structure comprisingfirst and second elongated partially cylindrical sections connected to abridge section, said first elongated partially cylindrical section andsaid second elongated partially cylindrical section comprising a firstporous structure, said elongated prosthesis structure comprising aprosthesis proximal end and a prosthesis distal end disposed oppositesaid first proximal end, said bridge section comprising a bridge sectionproximal end and a bridge section distal end disposed opposite saidbridge section proximal end and proximate said elongated prosthesisdistal end, said bridge section distal end comprising a first taperedregion configured and adapted to disrupt at least articular cartilageand cortical bone, said first elongated partially cylindrical sectioncomprising a first internal lumen, said second elongated partiallycylindrical section comprising a second internal lumen,
 2. Theprosthesis of claim 1, wherein said bridge section comprises a secondporous structure.
 3. The prosthesis of claim 1, wherein said elongatedprosthesis structure further comprises an osteogenic composition.
 4. Theprosthesis of claim 3, wherein said first internal lumen of said firstelongated partially cylindrical section is adapted to receive saidosteogenic composition therein.
 5. The prosthesis of claim 4, whereinsaid first elongated partially cylindrical section further comprises aplurality of slots in communication with said first internal lumen ofthe first elongated partially cylindrical section, said plurality ofslots configured and adapted to allow said osteogenic composition to bedispersed out of said first internal lumen and delivered to saiddysfunctional SI joint when said elongated prosthesis structure isadvanced into said dysfunctional SI joint.
 6. The prosthesis of claim 3,wherein said second internal lumen of said second elongated partiallycylindrical section is adapted to receive said osteogenic compositiontherein.
 7. The prosthesis of claim 6, wherein said second elongatedpartially cylindrical section further comprises a second plurality ofslots in communication with said second internal lumen of the secondelongated partially cylindrical section, said second plurality of slotsconfigured and adapted to allow said osteogenic composition to bedispersed out of said second internal lumen and delivered to saiddysfunctional SI joint when said elongated prosthesis structure isadvanced into said dysfunctional SI joint.
 8. The prosthesis of claim 3,wherein said osteogenic composition comprises a bone morphogenic protein(BMP) selected from the group consisting of BMP-1, BMP2a, BMP2b, BMP3,BMP4, BMP5, BMP6, BMP7 and BMP8a.
 9. The prosthesis of claim 3, whereinsaid osteogenic composition comprises a biologically active agent. 10.The prosthesis of claim 9, wherein said biologically active agentcomprises a cell selected from the group consisting of a human embryonicstem cell, fetal cardiomyocyte, myofibroblast, and mesenchymal stemcell.
 11. The prosthesis of claim 9, wherein said biologically activeagent comprises a growth factor selected from the group consisting of atransforming growth factor-alpha (TGF-α), transforming growthfactor-beta (TGF-β), fibroblast growth factor-2 (FGF-2), and vascularepithelial growth factor (VEGF).